Disposition of lubbock's wrasse?

[Delphinus]

I have a single Cirrhilabrus lubbocki in a 90g, fish tankmates are a pair of A. ocellaris.

The wrasse is an absolute nervous wreck. If there is any movement whatsoever within 6' of the tank, he goes and hides in the rock.

I have, and have had, other fairy wrasses and their personalities have not been this bad. I know to an extent these are nervous fish in general (and tend to be jumpers), so this could just be a moot question, but .... I'll ask anyhow:

I guess I'm just wondering, could C. lubbocki simply just be a shyer fish than other fairy wrasses? Or is the fact that he is a single fish in a tank, most by himself, contributing to this? Would the addition of other lubbock's help or hinder this?

The reason I ask is I also have a pair of C. cyanopleura in a different tank, and the difference in personalities is remarkably striking. I understand that at the best of times, personality can be hit and miss but I mean the difference is quite striking. The cyanopleuras will come to the front and top of the tank whenever someone walks by, eager for any scrap of food to be put in the tank. To feed the lubbock's, I have to put food in the tank, and quickly retreat to the minimum distance, otherwise he won't even eat.

To continue the comparison, I've had the lubbock's since December, and the cyanopleuras since January or February. Of course the cyanopleuras were also quite shy and nervous at first, but they have settled in over time. They can of course startle easily too, but it's not as bad as the lubbock's.

So I guess are these guys just different on account of general behaviours of the species, or is it that they're paired up that the behaviour tends to be a little different?